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Neutron discovery
Beginner
Chadwick discovered the neutron in 1932.
Chadwick showed in 1932 that a neutral particle of about proton mass is ejected when alpha particles hit beryllium. It explained isotopes and enabled fission.
Neutrons penetrate easily as they are neutral.
Free neutrons decay with 10-minute half-life.
In more detail
James Chadwick discovered the neutron in 1932, showing that the nucleus contains uncharged particles with mass close to that of the proton. This explained the mass and isotopes of nuclei.
Real-world uses
- Neutron discovery led to the understanding of nuclear fission.
- Neutron sources are used in research and materials testing.
- Chadwick's discovery of the neutron explained why nuclei have more mass than their protons alone would give.
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Frequently asked questions
Why was the neutron hard to detect?
It has no charge, so it does not produce the ionisation that charged particles do.
Who discovered it?
James Chadwick, in 1932.
Why was the neutron hard to detect?
It has no electric charge, so it does not leave tracks in detectors the way charged particles do.
Related topics in Atomic & Nuclear Physics
Nuclear fusion · Fusion in stars · Fusion reactors · Neutrinos · Radiation detection · Interaction of radiation with matter